Thank you very much, like I said I just threw up a picture when I inherited the subreddit, but it has always annoyed me..

As far as changing the position and links, I checked out the style page and that stuff wasn't there, I'll bugger around with CSS some other time. Currently I'm starting the Fleet guide, check /r/4xgaming soon.

(the opposite is true in space, larger volume = more efficient thrusters)

If you're talking about reality, I really don't think this is true.

No, I literally mean a chemical thruster is more efficient the more volume it has. Yes, your other points are true though. However, since both the tonnage required to brace acceleration and the amount of thrust generated follow the same volume vs. surface area proportions, a real life ship design should theoretically achieve the same acceleration no matter how you scale it. I guess I could have stated that better as "this is not true in space, where friction does not need to be accounted for".

6 – Combined arms failure

Real life Naval Combined Arms exists for three reasons, s'far as I can tell- Speed vs. Firepower, Money, Fog of War

Speed vs. Firepower. You can either have a fast ship that can outmaneuver the enemy, but has less armor, or a slow ship built like a tank. Doctrinally, if you have trade routes to defend, you need fast ships to catch raiders, which are fast to avoid being caught. If you have to defend against an enemy fleet, you need floating castles. The larger a ship is, the slower it is. (the opposite is true in space, larger volume = more efficient thrusters)

Money. Of course, if you could, you'd have a fleet of nothing but cruisers and battleships. However, you have too much ground to cover, and the more targets for your enemy the better.

Fog of War. Tied into the money conundrum, pickets, scout cruisers and anti-sub vessels are just as important as ships of the line.

But, basically it all comes down to the ratio of money to ground needed to be covered, and fast ships being just as viable (but in very different ways) as slow ships strategically and tactically.

If you can disrupt the enemy's trading with fast ships, but said ships are vulnerable to slightly slower, but slightly more powerful ships, then you will instantly create an ecosystem of ship classes, from tiny raiders and orbital defense craft to Death Stars. Deep space must then have a reason to exist, other than being a simple buffer as it is in pretty much every single game. This requires that space be completely open and ships can move around just as if they were on an ocean. You must be able to intercept trade ships in deep space, where they are alone and away from the protection of planets.

There can be no instant teleportation, and ships must be relatively slow, ~5-10 turns or a couple of minutes between systems (assuming a relatively small system count). No omniscient scanners either, tear a page out of Aurora's hefty tome and take a look at their detection system (or Hearts of Iron if you're doing square/hex/region based). This also incentivises outposts and patrols. When was the last time you had ships actively patrolling your border in a game? Never, for me.

I stress again, that the balance of empire income vs. fog of war mitigation has to be finely tuned, else you end up with an incentive to create nothing but battleships.

The Ion Defense will adsorb the attack by the Ion Weapon at all but the shortest of ranges due to damage drop off. However, if the enemy has more than one Ion Weapon, the Ion Defense won't be able to absorb it because it has been disabled by the other Ion shot, so having only one Ion Defense will not protect you from multiple weapons.

When you get to the point where you're invading a heavily defended world with a big space port and multiple defense stations and they all have like 10 Ion cannons, putting 10 Ion Defense on each of your troop ships costs 20 size, definitely a doable trade-off.

Yes, I have tested this myself, it's how I know :P I used to assume that only one was sufficient... and found out the hard way that it isn't. RIP the 1,000,000 soldiers of Free Terra that died in the cold of space above the Gizurean homeworld.

I've thought about this before but nothing really fits that well. Since games usually don't have dynamic empire creation or deterioration, and very little emphasis on trade.

Making a special tech tree for the Empire that makes their stuff worse and disallows them from building things is easy enough, but making it so new nations start popping up is a rare thing to be able to mod.

Off the top of my head-

Distant Worlds has a scenario editor which you can use to set up the map, then add some events if you want, like making the Empire's global happiness level take a nose dive- which will cause it to be automatically broken up into separate empires as worlds rebel. Also, having pirates set to many and regenerating would be fitting.

I feel like Space Empires might be doable with some modding work, but I don't have a whole lot of experience with it.

Star Ruler would likely be moddable to do this, but it would take a lot of work- like total conversion level.

And I feel like I'm missing a very obvious one, but I can't think of anything else...